Fire alarm box retention device



H. F. STREBEL El AL FIRE ALARM BOX RETENTION DEVICE Filed May 11, 1936 2Sheets-Sheet 1 gfohn R'fies Henry F fiirebel INVENTORS:

ATTORNEY5 'Oct- 3 H. F. STREBEL ET AL 2,175,976

FIRE ALARM BOX RETENTION DEVICE John [Cries Hen/ y]? Sirebel INVENTORSATTOI-QNEYS Patented Oct. 10, 1939 UNITED STATES FIRE ALARM BOXRETENTION DEVICE Henry F. Strebel, Garden City, and John Kries,

I Glendale, N. Y.

Application May 11, 1936, Serial No. 79,192

2 Claims.

The present invention relates to fire alarm equipment and moreparticularly to devices associated with a fire alarm box and adapted toretain the operator of an alarm until the arrival of the fire apparatus.

The general object of the invention is to obviate the occurrence offalse alarms by providing means operated coactively with the sending ofan alarm, by which the operator is retained.

Another object of the invention resides in providing a fire alarmretention device of simple and rugged construction in combination withan alarm system control, the operation of which will actuate theretention device so that the arm of the operator is engaged untilreleased by an authorized person.

The invention will be fully and comprehensively understood from aconsideration of the following detailed description when read inconnection with the accompanying drawings which form part of theapplication.

In the drawings:

Fig. 1 is a perspective view of a typical fire alarm box equipped withthe retention device preparatory to sending an alarm.

Fig. 2 is a fragmentary perspective view of the fire alarm box after thealarm has been sounded.

Fig. 3 is a rear elevational view of the fire alarm box, portions of thecasing being broken away to illustrate the mechanism comprising theretention device and the alarm control apparatus.

Fig. 4 is a transverse sectional view through the alarm box taken on theplane 4-4 of Fig. 3; and

Fig. 5 is a fragmentary sectional view taken on the plane 5-5 of Fig. 3,and illustrating the means for locking the actuating mechanism againstreverse operation.

Figure 6 is a detailed view of the bevelled gears for operating thedevice and illustrating a preferred means of distorting one of the gearteeth to provide a friction means.

Reference is now directed to the drawings for a more detaileddescription thereof, in which the numeral 6 indicates a typical firealarm box provided for housing a fire alarm sounding equipment.Preferably in the front panel of the box 6 is formed an aperture 1fitted with a suitable door 8 to provide a closure for same.

The aperture 1 is of a minimum size to admit the hand of an operator,and has associated therewith a sliding member or gate 9 arranged to forma partial closure for the aperture 1. The gate 9 is slidably retained onthe inner surface of the box 6 by a suitable means such as the guide-Ways la so that the gate 9 upon being actuated will move across theaperture 1 and thus diminish the free area thereof.

The gate 9 is provided with an inwardly extending box 9a so as toprevent the grasping of the lower edge of the gate 9 after same has beenlowered slightly by the'initial movement of the operating mechanism,hereinafter described. Were it possible for the operator to grasp thegate 9, the sounding of an alarm could be effected by withdrawing theoperators hand and further operatingthe mechanism by a downward pull onthe gate 9. The actuation of the gate 9 is accomplished by meanscomprising the gear rack l secured to the gate 9 and arranged to meshwith a gear I l affixed to a rotatable shaft l2, the shaft l2 beingjournalled in bearings 13.

As afore indicated the primary function of the apparatus is to operate afire alarm switch or other alarm control element coactively with theactuation ofthe retention device comprising the gate 9. To accomplishthis a rod I4 is secured to the gate 9 to project longitudinally fromsame and has its free end flexibly engaged to a rockable lever arm IS,the latter being swingably mounted on the stud l6 secured to a wall ofthe box 6. Suitably-arranged on thefree end of the lever arm I isa-contact plate l8, the same being electrically insulated from the armby the insulator IS. The numeral 20 indicates a pair ofelectricalterminals which form part of the alarm sounding equipment,-andto which the wires forming the alarm circuit may be connected. Thecontacts 20 are supported on a suitable bracket 2! being insulated fromthe same, and so disposed that when the gate 9 is lowered the contactplate l8 engaging the contacts 20 completes the alarm circuit, thisposition of the arm l5 being shown in phantom.

It will be seen from the foregoing that the lowering of the gate 9 toconstrict the aperture 7 and coactively close the alarm circuit may beaccomplished by the rotation-of the shaft I2 in the. direction indicatedby the arrow in Fig. 4. The rotation of the shaft l2 may be accomplishedby suitable means such as thatcomprising the bevel gear 22 carried onthe shaft l2 and arranged to mesh with a second gear 23. The gear 23 issecured to a shaft 24 journalled in a bracket 25, the opposite end ofthe shaft 24 being equipped with a suitable operating device such as thehand wheel 26.

It will be seen that the rotation of .the hand wheel 26 will cause thelowering of the gate 9 until same engages the wrist of the operator and,coactively the alarm circuit is closed by raising the plate l8 intocontact with the terminals 21!.

In order to defeat an attempt of the operator to release himself byrotating the hand wheel 26 in the reverse direction, a locking mechanism21 is provided as shown more clearly in Fig. 5. To the shaft I2 is fixeda ratchet wheel 28, the same being contained in a full sided housing 29.A weighted pawl 30 being pivotally mounted is disposed to engage theteeth of the ratchet wheel 28 to prevent the actuation of the shaft I2in a reverse direction.

To provide authorized access to the interior of the box 6, a lockequipped door 3| is provided thereon. After the arrival of the fireapparatus an official may release the sender of an alarm by opening thedoor 3| through which the pawl 30 may be released from the ratchet wheel28 by raising the pawl 39 by means of a lever 32 pivoted on a stud 33,the lever 32 being operatively connected to the pawl 30 by a rod 34. Therod 34 is loosely coupled to the pawl 30 by a slip joint 35 so as topermit the free movement of the pawl 30, independent of the lever 32. Toassure that the gate 9 be lowered entirely until the wrist of theoperator is engaged, the gate 9 after its initial movement is lowered bygravity, and is accordingly weighted as indicated at 39. Although theoperator may release the hand wheel 26 after the initial operation, thesounding of the alarm and the retention of the operator will be effectedsince the gate 9 will be lowered by gravity, and thus close the alarmcircuit. To hold the gate 9 in its raised position until after theinitial movement of same has been effected, suitable frictional meansmay be employed on the shaft I2. It is preferred to accomplish thiseffect by enlarging or otherwise deforming one or more of the teeth ofeither of the gears 22 or 23, which teeth are in mesh as the gate 9 isin its uppermost position. For purposes of illustration, Figure 6discloses a deformed gear tooth 31, which tooth when in mesh with thegear 22 will eiTect suitable friction means for holding the gate 9 inits raised position until after the initial movement of same has beeneffected. It is to be understood, however, that more than one tooth canbe distorted should it be necessary to hold the gate in raised position.Thus a sufficient amount of power applied to the hand wheel 26 isrequired to overcome the friction effected by the distorted gear tooth31 until the initial movement of the gate 9 is effected, after which theweight 36 functions to complete the operation of the device independentof the mechanism operating means.

It is to be understood that this improvement is capable of extendedapplication and is not confined to the exact showing of the drawings norto the precise construction described and, therefore, such changes andmodifications may be made therein as do not affect the spirit of theinvention nor exceed the scope thereof as expressed in the appendedclaims.

What is claimed as new is:

1. A fire alarm apparatus of the type described comprising a casinghaving an aperture formed in a side thereof adapted to permit passage ofa human hand therethrough, means for reducing the area of said aperturewithout entirely closing same whereby passage of a human handtherethrough can be controlled, said means comprising a gate positionedwithin said casing adjacent but normally above said opening and slidablein guideways afiixed to parts of said casing, said gate including a boxextending inwardly therefrom and upwardly from the lower edge thereofand terminating adjacent the opposite wall of said casing, a weightedelement within said box fer moving said gate by gravity over saidopening, means for holding the gate in its raised position, comprising arack on said gate, a pinion engaging the rack, a gear train operativelyconnected to the pinion, one or more teeth of a gear in said train beingdeformed to prevent interaction of the gears for rotation of the pinion,means within the casing to force interaction of said deformed gear andtrain, whereby downward movement of the gate may be initiated, saidmeans comprising a hand wheel operatively connected to the gear train,means actuated by downward movement of said gate for signalling analarm, means for precluding unauthorized lifting and counter-movement ofsaid gate comprising a ratchet wheel and pawl associated with andsimultaneously actuable by said gear whereby upward movement of the gateis prevented While said pawl and ratchet are in engagement, and meansaccessible only through a manually locked door in said casing forreleasing said ratchet, thereby permitting raising of the gate.

2. A fire alarm apparatus of the type described comprising a casinghaving an aperture formed in a side thereof adapted to permit passage ofa human hand therethrough, means for diminishing the size of saidaperture without entirely closing same whereby passage of a human handtherethrough can be controlled, said means comprising a gate positionedwithin said casing adjacent but normally above said opening and slidablein guideways aifixed to parts of said casing, said gate being weightedso as to move by gravity over said opening, means for holding the gatein its raised position, comprising a rack on said gate, a pinionengaging the rack, a gear train operatively connected to the pinion, oneor more teeth of a gear in said train being deformed to preventinteraction of the gears for rotation of the pinion, means within thecasing to force interaction of said deformed gear and train, wherebydownward movement of the gate may be initiated, said means comprising ahand wheel operatively connected to the gear train, means actuated bydownward movement of said gate for signalling an alarm, means forprecluding unauthorized lifting and counter-movement of said gatecomprising a ratchet wheel and pawl associated with and simultaneouslyactuable by said gear whereby upward movement of the gate is preventedwhile said pawl and ratchet are in engagement, and means accessible onlythrough a manually locked door in said casing for releasing saidratchet, thereby permitting raising of the gate.

HENRY F. STREBEL. JOHN KRIES.

